Pressure modulating system for reversing clutches and throttle control

ABSTRACT

A pneumatic clutch control assembly for a ship&#39;&#39;s propulsion system which sequentially controls the inflation and exhaust of pneumatically operated clutches and also controls the throttle system of an associated prime mover. Upon actuation of a control valve, which may be located in the pilot house and at other locations, a series of valves are sequentially operated to inflate a selected ahead or astern clutch in one of two conditions: (1) a first condition in which the clutch is inflated to reduced pressures according to the variable pressure of the control valve to allow slippage of the clutch and permit operation at speeds below the idle speed of the prime mover, and (2) a second condition in which the clutch is inflated to full pressure under a programmed inflation rate. In the first condition, the prime mover remains at minimum speed and only part of the idle torque is transmitted as required for the desired propeller speed. In the second condition, the control assembly limits the prime mover control signal during periods of partial clutch inflation until full pressure is supplied to the clutch.

United States Patent 1191 Phinney [111 3,727,737 1 Apr. 17, 1973PRESSURE MODULATING SYSTEM FOR REVERSING CLUTCHES AND THROTTLE CONTROLJohn M. Phinney, Milwaukee, Wis.

[73] Assignee: The Falk Corporation, Milwaukee,

Wis.

[22] Filed: June 14, 1971 [21] Appl.No.: 152,938

[75] Inventor:

[52] US. Cl. ..192/.098, 192/109 F, 91/413,

Primary E;c am ir1 er Benjamin W. Wyche Attorney-Donald G. Casser et al.

[5 7] ABSTRACT A pneumatic clutch control assembly for a shipspropulsion system which sequentially controls the inflation and exhaustof pneumatically operated clutches and also controls the throttle systemof an associated prime mover. Upon actuation of acontrol valve, whichmay be located in the pilot house and at other locations, a series ofvalves are sequentially operated to inflate a selected ahead or asternclutch in one of two conditions: (1) a first condition in which theclutch is inflated to reduced pressures according to the variablepressure of the control valve to allow slippage of the clutch and permitoperation at speeds below the idle speed of the prime mover, and (2) asecond condition in which the clutchis' inflated to full pressure undera programmed inflation rate. In the first condition, the prime moverremains at minimum speed and onlypart of the idle torque is transmittedas required for the desired propeller speed; In the second condition,the control assembly limits the prime mover control signal duringperiods of partial clutch inflation until full pressure is supplied tothe clutch.

5 Claims, 4 Drawing Figures PATENTEU APR 1 71975 SHEET .1 BF 2 NEUTRALINVENTOR JOHN M. PHINNEY SUPPLY ATTORNEY CONTRO ED BY GOVERNOR AIR OCHOKE VA VIZ-48 PATEIWED 3.727.737

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O l 3 4 5 6 7 a 9 TIME SECONDS CONTROLLED BY RELAY VALVE-Z6 IO H l2 IINVENTOR JOHN M.PHINNEY ATTORNEY PRESSURE MODULATING SYSTEM FORREVERSING CLUTCHES AND THROTTLE CONTROL BACKGROUND OF THE INVENTION 1.Field of the Invention The particular technology to which this inventionpertains is a ships propulsion system of the type incorporatingair-actuated clutches, and more specifically to a control panel assemblythat controls the air supply to pneumatically operated clutches of thepropulsion system and also controls the throttle speed of the shipsprime mover.

2. Description of the Prior Art Many different types of controlassemblies for air actuated clutches of a ships propulsion system havebeen designed. In an air actuated clutch arrangement, the clutch isengaged by the inflation of an inflatable rubber and fabric air glandbonded to an outer steel rim. Friction lining on the inner surface ofthe gland engages a cylindrical clutch drum when the gland is inflated.When the gland is fully deflated there is no clutch engagement and whenthe gland is fully inflated there is complete clutch engagement. Betweenthese two extremes the degree of clutch engagement corresponds to theamount of inflation of the gland and the amount of torque that theclutch can transmit is dependent upon the degree of clutch engagement.To be effective a clutch control should regulate the ships ahead andastern propulsion clutches in such fashion that:

l. The clutches may be partially engaged when the ships prime mover isat an idle throttle speed;

2. The clutches will not slip when the ships prime mover is at a highthrottle speed; and

3. Engagement of the ahead clutch may be quickly changed to engagementof the astern clutch, and vice versa, without excess slippage of theclutches or stalling of the ships prime mover.

One of the reasons for the above control requirements is to provide forship maneuverability when it is docking or traveling in a congestedarea. Under such conditions, the throttle speed of the ships prime moveris maintained at approximately idle speed and the particular clutchengaged must be in a slippage condition to transmit only a small amountof propulsive force to the ships propeller and to prevent stalling ofthe prime mover which would be caused by abrupt engagement of theselected clutch to its full operating pressure. Due to the fact that aship has no braking system, except for the reversal of its propulsionsystem, the ahead and astern clutches must also be capable of beingalternately engaged and disengaged to substitute for a braking system.During the transitions between engagement of the ahead clutch(es) andastern clutch(es), the clutch control must provide for the correctamount of engagement of the selected clutch that corresponds to thethrottle speed of the prime mover. lf this is not done and, for example,the selected clutch is fully engaged (i.e., inflated to full pressure)when the throttle speed of the prime mover is at idle, the prime movercould be stalled because the torque of the prime mover is not sufficientto drive the ships propeller. On the other hand, if the selected clutchis not sufficiently engaged to prevent slippage and the throttle speedof the prime mover is advanced to full speed, the selected clutch willburn out because of the heat produced as a result of the extremeslippage that would result. By accurately controlling the amount ofinflation, excess clutch slippage may be prevented without causing theprime mover to stall. The control of the inflation rate is provided by aclutch control assembly as disclosed in this application.

Prior art clutch control systems have generally attempted to achievesatisfactory operation of air actuated clutches by the use of multipletime delay arrangements that act to delay full engagement of theclutches until the throttle speed of the prime mover is sufficientlyfast to make certain that the prime mover will not stall. However, timedelay circuits have not proved completely satisfactory. One primaryproblem with a time delay control system is that once the system isactivated, full engagement of the clutches is controlled by the timedelays and engagement occurs at a set time after activation of thecontrol system regardless of the status of the throttle speed of theprime mover. The time delays may be varied to fully engage the clutchesat the proper time under normal operation, but if for some reason primemover throttle speed is not properly coordinated with clutch action, theprime mover may stall, or the engaged clutches .will be excessivelyheated.

A second primary problem with a time delay system is that it addsincreased complexity to the control system. The time delays normallyconsist of air tanks that must be filled with pressurized air to aspecific level before they pass on any pressurized air to other portionsof the system. Such pressurized air as provided on board a shipfrequently contains dirtparticles or oil and water globules that collectin the time delay tanks so as to vary the delay of the tank and therebyresult in unpredictable clutch and prime mover actuation. As a result,to maintain correct operation of the control system the tanks must bedrained quite regularly. If a problem does occur with the system inspite of regular maintenance, due to the complexity of the system withthe time delays it is often impossible to pin-point the source of theproblem, thus requiring that the entire control system be cleaned andchecked. Hence, time delay control systems have not provided fullysatisfactory clutch control systems.

SUMMARY OF THE INVENTION My present invention provides a pneumaticclutch control assembly for a ship's propulsion system that issequentially operated to regulate the inflation of air inflatableclutches and to correlate prime mover speed with the regulated clutchair pressure. This sequential system is comprised of a first valve meansthat has pressurized air supplied to it by a first and second airbranch. The first valve means is piloted by air pressure from the firstair branch to initially allow' air from the first branch to pass throughthe first valve means and begin inflating a selected clutch(es) througha third air branch that connects a first valve means to the clutches.When the air pressure of the first air branch reaches a pre-selected'level, the first valve means blocks the first air branch and permitsair pressure from the second air branch to complete inflation of theselected clutch through the third air branch. As the selected clutch isinflated, a piloting air branch is pressurized by air from the inflatedclutch to control the rate of inflation of the clutch above a setpressure level and also control throttle speed of the ships prime moverabove a different set pressure level.

The main objects of this invention are: to provide a clutch controlassembly that directly correlates the engagement of the inflatableclutches of the propulsion system to the acceleration of the throttlespeed of the systems prime mover; to provide a clutch control assemblycomprised of components that are sequentially operated to insure thateach event during engagement of the clutches cannot be achieved untilthe systems previous sequence is completed; to provide a controlassembly with a piloting means that is activated by the air pressure ofone of the clutches as the clutch is inflated, which piloting means whennot activated prevents acceleration of the throttle speed of the primemover beyond idle. A more limited object is to provide the particularstructures hereinafter claimed.

By the implementation of this invention, one of the primary advantagesachieved is that by having a direct correlation between engine throttlespeed and clutch engagement, the clutches will not engage in suchfashion that prime mover stalling results, and additionally the primemover throttle speed cannot be advanced unless the selected clutch(es)is sufficiently engaged to prevent any material clutch slippage. Asecond primary advantage is that this invention eliminates the need fortime delay arrangements that were previously necessary on prior clutchcontrol assemblies; thus, controlled actuation of clutches and primemover relationships is improved, the day-day maintenance issubstantially reduced and trouble shooting of the present invention isgreatly simplified.

The foregoing and other objects and advantages of the invention willappear from the following description. In the description reference ismade to the accompanying drawings which form a part hereof, and in whichthere is shown by way of illustration and not of limitation a preferredembodiment of the invention. Such embodiment does not represent the fullscope of the invention, but rather the invention may be employed in avariety of embodiments, and reference is made to the claims herein forinterpreting the breadth of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representationof a ships propulsion system incorporating the clutch control system,which may be that of the present invention;

FIG. 2 is a schematic representation illustrating a preferred embodimentof the present invention enclosed in dotted lines and connected toassociated components of the propulsion system of FIG. 1;

FIG. 3 is a graphical representation of the designed operation of anactual system constructed according to the present invention; and

FIG. 4 is a graphical representation of the actual operation of thesystem of FIG. 3 after the ship's throttle control has been rapidlymoved from a neutral position to its fully open position.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates apneumatically controlled propulsion system of a ship which includes apilot house control stand 1 which mounts a throttle lever 2 and fourpressurized air lines 3, 4, 5, and 6 operatively connecting the controlstand 1 to a clutch control panel assembly 7. All interconnectionsbetween the pneumatically controlled components of the propulsion systemconsist of similar type air lines, some of which are operating lines andthe remainder which are piloting lines. The operating lines have arelatively large flow capacity and are utilized to convey considerablequantities of air to various parts of the propulsion system. Thepiloting lines, on the other hand, have a relatively small flow capacityand are utilized to provide limited quantities of air to specific pointsin the system for control purposes. The air lines 4, 5 and 6 arepiloting lines which enable the panel assembly 7 to be controlled fromthe control stand 1. The air line 3 is an operating line through whichfull supply air from the ship's pressurized air source is supplied tothe control stand I.

The panel assembly 7 is connected to the ships pressurized air source bya main supply line 8 to feed the operating line 3. Supply air islikewise passed through the clutch control panel assembly 7 to bedirected to the throttle speed governor 9 of the ships engine 10 by apiloting line 11, and to a dual rotary air joint 12 by a pair ofoperating lines 13 and 14. The dual rotary air joint 12 is located onone end of a dual passage air shaft 15 which leads to an ahead clutch l6and an astern clutch 17, both attached to the opposite end of the shaft15. The clutches 16 and 17 act to transmit rotational drive force fromthe engine 10 connected through drive shaft 18 to a reverse reductiongear train 19. Because the engine 10 is unidirectional and also becauseits rotational drive force is high in speed but low in torque, thereverse reduction gear train 19 functions to reduce the rotational speedof the engine drive force to increase the drive force torque and also toreverse the direction of the drive force when desired. The gear train 19has an output shaft 20 that drives a propeller shaft 21 on which theship's propeller 22 is carried.

The control lever 2 is movable forwardly or rearwardly as indicated byFIG. 1 to select the ships direction of travel, whereupon supply air isdirected to the appropriate clutch 16 or 17 which'then transmitspropulsive force through the reverse reduction gear train 19 to thepropeller 22. The clutch control panel assembly 7 serves to control therate of engagement of the selected clutch 16 or 17 and concurrentlyregulate the throttle speed governor 9.

A schematic representation of the clutch control panel assembly 7 in astandby mode is shown in FIG. 2 enclosed by dotted lines. Also shown inFIG. 2 are the various components of the propulsion system with whichthe panel assembly 7 connects. The propulsion system of the ship isactivated by the throttle lever 2 shown in a neutral position. Movementof the throttle lever 2 provides full control over the ship's propulsionsystem by activating a pressure control and directional flow controlthrottle valve 23. The throttle valve 23 is designed to furnish fullsupply air pressure to one of the two piloting lines 5 and 6 andgraduated pressure to the third piloting line 4. All of the valvesemployed in the present invention are well known by those skilled in theart of pneumatic valve control and similar valves can be readilypurchased in the market place. I-Ience, structural details of theemployed valves will not be described herein. The lever 2 is equippedwith an adjustable friction brake, not shown, that holds the lever 2 inany selected position. If the lever 2 is pivoted 5 backward or forwardof its neutral position full supply air pressure is supplied to line 5or 6 respectively. However, the pressure in the piloting line 4 isalways proportional to the pivotal movement of the lever 2. As indicatedby FIG. 1 movement of the lever 2 to either side of its neutral positioninitially places the propulsion system in a slip operation which meansthat there is not enough air in either of the clutches 16 or 17 toprevent clutch slippage even though the ships engine is at idle throttlespeed throughout the slip range. As the lever 2 is progressively pivotedbackward or forward of its neutral position, through and beyond the sliprange, the pressure in line 4 increases until it reaches its maximum atthe point when the lever 2 reaches its limit of movement in thatparticular direction.

The piloting line 4 leads to a valve means that forms part of a firstair branch and also connected to the line 4 is a bleeder valve 25 whosefunction will be described later. The valve means consists of a repeatvalve 26 that has three ports, an inlet port 27, an outlet port 28 and apiloting port 29 to which the piloting line 4 is coupled.

The main air supply line 8 leads to the repeat valve inlet port 27. Therepeat valve 26 is designed to relay or repeat large quantities ofsupply air through the inlet port 27 to the outlet port 28 at a pressurelevel corresponding to the air pressure in the piloting line 4. Thus, ifair at 15 psi is supplied to the piloting port 29 by the line 4, thepressure level of the air that exits from the outlet port 28 will alsoequal 15 psi. The reason that the repeat valve 26 is included in thefirst air branch is that it provides a large quantity of air whereasonly a limited quantity of air is provided by the throttle valve 23 tothe piloting line 4. v

The repeat valve outlet port 28 is connected to an operating line 30that also forms part of the first air branch and leads to a first inletport 31 of a master control valve 32. The master control valve 32 has asecond inlet port 33 that connects to a second air branch, a commonoutlet port 35 that connects to a third air branch and a piloting port37. The valve 32 is a pneumatic-piloted, pressure sensitive valve thatchanges the air passages within itself when air at a first controlpressure, or higher, is supplied to its piloting port 37. Air pressureis supplied to the piloting port 37 by a piloting line 38 that iscoupled to the operating line 30 leading from the repeat valve 26. Thus,air at an equal pressure level is supplied to both the inlet port 31 andthe piloting port 37 of the master control valve 32, which pressure isat the same level as that supplied by the throttle valve 23 to thepiloting line 4. if a piloting air pressure less than the first controlpressure is directed to the master control valve piloting port 37, thefirst inlet port 31 communicates with the outlet port 35, and thepressurized air delivered .from the repeat valve 26passes unimpededthrough the master control valve 32 into the third air branch.

The third air branch operatively connects the master control valveoutlet port 35 to the clutches l6 and 17. Comprising a portion of thisthird air branch is an operating line 39 that conveys the operating airexiting from the master control valve outlet port 35 to an inlet port 40of a clutch selector valve 41. The clutch selector valve 41 has twoadditional inlet ports 42 and 43 and also four outlets ports 44, 45 46and 47. The inlet ports 42 and 43 connect to the lines 5 and 6 leadingfrom the throttle valve 23. As previously explained, by moving thecontrol lever 2 five degrees backward or forward of its neutralposition, full supply air pressure is delivered to either the line 5 orthe line 6 respectively. This pressurized air actuates the valve 41 todirect the operating air coming into the inlet port 40 to one of theoutlet ports 44 or 45. Connected to these outlet ports 44 and 45 are theoperating lines 13 and 14 respectively, which lines 13 and 14 serve forconveying the operating air passing through the clutch selector valve 41to one of the clutches 16 or 17 to begin its inflation. The outlet ports46 and 47 of the clutch selector valve 41 are exhaust ports, one foreach inflatable clutch l6 and 17 respectively. During the inflation ofthe ahead clutch 16, the astem clutch 17 is deflated through itscorresponding exhaust port 47, and vice versa. When the control lever 2is in its neutral position, both clutches 16 and 17 are exhausted to theatmosphere through their respective exhaust ports 46 and 47 creating aneutral condition. This completes the description of the components ofthe control assembly 7 that: are

employed to inflate the clutches l6 and 17 from zero to the firstcontrol pressure established for the valve 32. So long as air at apressure level less than the first control pressure is supplied to themaster control valve piloting port 37 the above described inflationprocess will occur and one of the clutches 16 or 17 will variablyinflate to a pressure that equals the pressure level of the air suppliedto the inlet port 31 of the master control valve 32.

When the position of the lever 2 is such that air at a pressure greaterthan the first control pressure is supplied through the repeat valve 26to the piloting port 37 of the master control valve 32, the valve 32actuates to disconnect the first air branch from the third air branchand place the second air branch in communication with the third airbranch. The second air branch is operatively interjacent the main airsupply line 8 and the second master control valve inlet port 33.Included in the second air branch are achoke valve 48 and apneumatically-piloted, pressure sensitive boost valve 49 connected inparallel with one another. Normally, the second inlet port 33 of themaster control valve 32 does not communicate with the outlet port 35 ofthe valve 32, which prevents air flow in the second air branch. But whenthe master control valve 32 actuates, communication exists between theports 33 and 35 whereupon the parallel combination of the choke valve 48and the boost valve 49 comes into play and air begins to flow throughthe choke valve 48. The choke valve 48 has an inlet port 50 and anoutlet port 51. The boost valve 49 has an inlet port 52, an outlet port53 and a piloting port 54. An operating line 55 connects the inlet port50 of the choke valve 48 to the air supply line 8. Another operatingline 56 is coupled to the line 55 to operatively connect the inlet port52 of the boost valve an operating line 57, and an operating line 58connects the outlet port 53 of the boost valve 49 to the line 57.

When piloting pressure actuates the master control valve 32, the chokevalve 48 permits air to flow through the second air branch at aprogrammed rate that is determined by the size of the choke valve 48. Inthis way, inflation of one of the clutches 16 or 17 beyond the firstcontrol pressure is initially controlled by the choke valve 48. There isno immediate flow through the boost valve 49 at this time because thethru-passage between the inlet port 52 and the outlet port 53 of thepneumatically controlled pressure sensitive boost valve 49 is normallyblocked until piloting air at a second control pressure above the firstcontrol pressure is directed to the boost valve piloting port 54. Thepiloting air pressure for the boost valve 49 is operatively suppliedfrom the clutch 16 or 17 that is being inflated as will be describedmore fully below. When clutch pressure reaches the second controlpressure level, the thru-passage between the boost valve inlet 52 andoutlet 53 ports will become unblocked and air will be allowed to flowunimpeded through the boost valve 49, bypassing the choke valve 48 torapidly complete inflation of the selected clutch 16 or 17 to the fullpressure level of the supply air. Hence, the sequential action of clutchinflation over the first control pressure is that air is suppliedthrough the choke valve 48 of the second air branch at the programmedrate until the clutch pressure reaches the second control pressure atwhich time the boost valve 49 actuates and substantially unimpededsupply air is furnished to the inflating clutch 16 or 17 to complete itsinflation to the full pressure of the air supply source.

The air pressure that controls the boost valve 49 is provided by apiloting circuit that is at actual clutch inflation pressure since it isconnected to the operating lines 13 and 14 that feed the clutches l6 and17 respectively. The boost valvepiloting circuit is comprised ofashuttle valve 60 and a number of associated piloting lines. Attached tothe operating line 13 is a piloting line 61 that leads to an inlet port62 of the shuttle valve 60 and, likewise, operating line 14 has anattached piloting line 63 that leads to an inlet port 64 of the shuttlevalve 60. The shuttle valve 60 automatically selects and directs theflow of air from one of the two piloting lines 61 and 63 to a commonoutlet port 65 without destroying the segregation between the lines 61and 63. This selection is made by choosing air from the line 61 or 63that has the highest air pressure. Connected to the shuttle valve outletport 65 is a piloting line 66 that extends to the boost valve pilotingport 54. Thus, air is siphoned from one of the clutches 16 or 17 by oneof the piloting lines 61 or 63 respectively and is directed through theshuttle valve 60 to the boost valve piloting port 54 to actuate theboost valve 49.

This completes the description of the components that are employed toprovide the controlled rate of inflation of the clutches 16 and 17 thatthe present invention was designed to achieve. The components of thecontrol panel assembly 7 now to be described provide regulation of thethrottle speed governor 9 which is achieved through a throttle governorvalve 67 that is similar to the master control valve 32 and the boostvalve 49 in that it is pneumatically-piloted and pressure sensitive. Thegovernor valve 67 has an inlet port 68,

first and second outlet ports 69 and 70 respectively and a piloting port71. The inlet port 68 is connected to the operating line 30 leading fromthe repeat valve 26 by an operating line 72 in order that the inlet airpressure to the governor valve 67 directly corresponds to movement ofthe throttle lever 2 which, as previously explained, determines thepressure of the air in the operating line 30. The first outlet port 69of the governor valve 67 is operatively connected to the throttlegovernor 9 by an operating line 1 1 and the second governor valve outletport 70 serves as an exhaust port to exhaust the line 1 1 to theatmosphere when the governor valve 67 is unactuated.

Piloting of the governor valve 67 is provided by a piloting line 73 thatleads from the boost valve piloting circuit and is connected to thegovernor valve piloting port 71. When the throttle lever 2 is in itsneutral position, the governor valve thru-passage lying between theinlet port 68 and the first outlet port 69 is blocked and the throttlecontrol governor 9 maintains the engine 10 at an idle. The governorvalve 67 is constructed to maintain this state until the pressure levelof its piloting air reaches a third control pressure which is higherthan the first and second control pressures. Thereupon, the valve 67actuates to unblock the passage between the inlet port 68 and the firstoutlet port 69. Air is then directed through the operating line 11 tothe throttle governor 9 which begins to accelerate the engine. Since thegovernor valve piloting pressure is provided by the boost valve pilotingcircuit that directly reflects inflated clutch pressure, this means thatif the piloting pressure for the governor valve 67 equals the thirdcontrol pressure, the clutch pressure is at the same level, and thislevel is selected so there will be sufficient pressure to preventsignificant clutch slippage when the engine 10 begins accelerating. Itshould be kept in mind that although clutch pressure must equal orexceed the third control pressure for the governor valve 67 to actuate,once the first control pressure is reached in the first air branch, thesecond air branch is actuated to complete clutch inflation, and airpressure in the first air branch no longer corresponds to clutch airpressure. Therefore, the pressure in the line 72 feeding the governorvalve inlet port 68 always equals the variable pressure corresponding tothe signal in the piloting line 4.

Upon actuation of the governor valve 67, any movement of the throttlelever 2 in a direction away from its neutral position will increase theair pressure of the air relayed by the repeat valve 26 to the operatingline 30 and correspondingly the throttle speed of the engine 10 willaccelerate. When it is desired to decelerate the throttle speed of theengine 10, the throttle lever 2 is simply pulled back toward its neutralposition. Air is then exhausted from the piloting line 4 by the bleedervalve 25 connected between the throttle valve 23 and the repeat valve26. The bleeder valve 25 is utilized to exhaust the line 4 to reduce thehysteresis effect that would be produced if the line 4 was exhaustedthrough .the pressure regulating portion of the throttle valve 23.

The repeat valve 26 relays the decrease in the pressure of the line 4 tothe engine governor 9 through the governor valve 67 and a reduction inthrottle speed results.

EXAMPLE To briefly summarize the sequential operation of the controlpanel assembly 7 and more clearly show the correlation between movementof the lever 2, clutch inflation pressure and engine throttle speed, theaction of the panel assembly 7 will be described with respect tomovement of the throttle lever 2 as it is pivoted slowly to a full openthrottle position to inflate the ahead clutch 16. Inflation of the astemclutch 17 would produce the same sequential action as will be describedexcept that the components that relate to the inflation of the asternclutch 17 would be utilized.

This description is made with reference to a specific example of anactual system constructed according to this invention and utilized onthe m/v City of Lisbon, a 150 foot tuna clipper with an engine producing3,500 horsepower at an engine speed of 900 .R.P.M. FIG. 3 is a designgraph for the system of this example showing the status of the airpressure in clutch 16 versus the position of the throttle lever 2 withthe primary events that occur during clutch inflation specificallyindicated on the graph. As the throttle lever 2 is pivoted forward 5from its neutral position, piloting air pressure is furnished to theclutch selector valve 41 through the piloting line 6. This air pressureactuates the clutch selector valve 41 in such manner that it is set upto direct operating air supplied to its inlet port 40 to the aheadclutch 16. Thereafter, further movement of the throttle lever 2 resultsin the supplying of piloting air to the repeat valve 26 through the line4. In response to this piloting air the repeat valve 26 relays operatingair through the first air branch to the master control valve 32 whichallows the air from the first air branch to pass into the-third airbranch to begin inflating the ahead clutch 16. Continuing movement ofthe lever 2, at the ahead clutch 16 is inflated to psi which issufficient pressure for the clutch 16 to begin transmitting propulsiveforce from the engine 10. It is at this lever position that maximum slipis realized which permits the ship to be propelled at minimum shipspeed.

With 25 of lever movement, air pressure of the clutch 16 equalsapproximately 20 psi. At this level of clutch inflation, the engine 10is still at an idle but there is no longer any clutch slippage. Thus,maximum idle throttle ship speed is achieved. This transition frommaximum slip/minimum speed to minimum slip/maximum speed occurs during alever movement of 15. Throughout this 15 range of lever movement clutchslippage is directly related to the position of the lever 2, hence, shipspeed is easily controlled. Further movement of the lever 2 from to doesnot change ship speed but at 30 of lever movement, there is 25 psi ofpressure established as the first control pressure of the installationof this example, in the first air branch and the master control valve 32actuates to permit the second air branch to complete the inflation ofthe,

graph of FIG. 4 which is a graph of the operation of the system as abovedescribed, depicting the change in clutch air and throttle governor airas the throttle lever 2 is quickly pivoted from its neutral position toa full throttle position. As can be seen from this graph, the periodduring which the clutch pressure substantially increases coincides witha rapid increase in throttle governor pressure, which pressure isdirectly proportional to engine speed. Hence, both stalling and clutchslippage are prevented even though the engine throttle speed is rapidlyincreased.

By keying the acceleration of the engine 10 to the clutch air pressurethrough the use of the governor valve 67 and isolating the first airbranch from the second air branch, not only is the need for time delaycircuits eliminated but in addition, reversal of clutch engagement maybe smoothly, consistently, and efficiently accomplished. For example,assume the ahead clutch 16 is engaged with maximum supply pressure andthe engine 10 is at full throttle. Further assume that it is desired todrive the propeller 22 astem as quickly as possible. With the sequentialaction of the present invention, this may be carried out by simplypivoting the control lever 2 from its extreme forward position to itsextreme rearward position. Due to this movement of the lever'2, theclutch selector valve 4l is actuated by the throttle valve 23 tooperatively connect the ahead clutch 16 to the clutch select valveexhaust port 46 and operatively connect the astern clutch 17 to theclutch selector valve inlet port 40. Immediately the air pressure of theahead clutch 16 is exhausted .to the atmosphere while inflation of theastem clutch l7 begins. With the drop in ahead clutch air pressure theline 73 supplying piloting pressure to the governor valve 67 isexhausted through the exhaust port 46 of the clutch selector valve 41causing the governor valve 67 to deactuate and the engine throttle speedto decelerate to idle. Although ahead clutch pressure is reduced toward0 psi, throttle speed of the engine 10 is correspondingly reduced andharmful clutch slippage is prevented. Before the engine throttle speedcan again be accelerated to full throttle the inflation pressure of theastem clutch 17 must rise to the actuation pressure of the governorvalve 67. Full inflation of the astern clutch 17 is delayed, however, byreason of the fact that when the ahead clutch 16 is exhausted, thepiloting port 54 of the boost valve 49 is also exhausted and the boostvalve 49 deactuates. As a'result the inflation of the astem clutch 17 isagain through valves 26, 48 and- 49 at a rate such that the engine 10 isnot stalled by the clutch engagement nor will significant clutchslippage occur. All of this action is, of course, controlled by thesequential action of the clutch control assembly 7.

CONCLUSION The embodiment of the invention shown and described hereinprovides an improved marine drive clutch control system through theutilization of a first and a second selective inflation means. The firstinflation means is illustrated as comprising the first air branch, themaster control valve 32 and the third air branch. The second inflationmeans is illustrated as comprising the second air branch, the mastercontrol valve 32 and the third air branch. The first selective inflationmeans initially begins the inflation of a selected clutch until airpressure in the first air branch reaches a pre-selected level.Thereupon, the master control valve 32 actuates and inflation of theselected clutch is completed through the second selective inflationmeans. As the selected clutch is inflated, a pair of piloting airbranches are pressurized by air from the selected clutch to control therate of inflation of the clutch above a set pressure level and alsoallow advancement of the throttle speed of the ship's prime mover abovea different set pressure level. Thus, it is seen that the presentinvention provides an extremely certain method of sequentiallycontrolling the clutches of a ship's propulsion system to insure thatengagement of the clutches will at all times relate to the throttlespeed of the ship's engine.

Although a specific example of this invention has been herein describedin order to illustrate the invention, it is expected that changes can bemade in the described embodiment and that other embodiments can bedesigned by those skilled in the art which will remain within the truespirit and scope of this invention.

lclaim:

l. A pneumatic clutch control assembly for a marine propulsion system ofthe type including a prime mover controlled by a throttle speedgovernor, a gear drive for transmitting power from the prime mover to apropeller drive shaft, air inflatable clutches arranged to selectivelyconnect the prime mover to the gear drive including at least one suchclutch for ahead operation and at least one'such clutch for asternoperation, and throttle means for actuation of the propulsion system,

said pneumatic clutch control assembly being adapted for connection to asource of pressurized air and comprising, in combination:

a first selective inflation means that is controlled by the throttlemeans to inflate a selected one of said air inflatable clutches up to afirst control air pressure at a rate responsive to actuation of thethrottle means;

a second selective inflation means that operates independently of andbypasses the throttle means for inflating said selected air inflatableclutch beyond the first control air pressure at a programmed rate up toa second control air pressure at which point the second selectiveinflation means is actuated by clutch air pressure to complete inflationof said selected clutch at an unrestricted rate to full clutch airpressure;

valve means arranged to operatively connect the first selectiveinflation means for clutch inflation below the first control airpressure and further arranged to operatively connect the secondselective inflation means for clutch inflation above the first controlair pressure;

a throttle governor control means adapted to control the throttle speedgovernor to maintain the prime mover at idle speed until the selectedclutch air pressure reaches a third control air pressure and thereafterallow air pressure from said first selective inflation means to besupplied to the throttle governor for regulation of engine speed by thethrottle means.

2. A pneumatic clutch control assembly for a marine propulsion system ofthe type including a prime mover controlled by a throttle speedgovernor, a gear drive for transmitting power from the prime mover to apropeller drive shaft, air inflatable clutches arranged to selectivelyconnect the prime mover to the gear drive including at least one suchclutch for ahead operation and at least one such clutch for asternoperation, and throttle means for actuation of the propulsion system,

said pneumatic clutchcontrol assembly being adapted for connection to asource of pressurized air and comprising, in combination:

a first selective inflation means that is controlled by the throttlemeans to inflate a selected one of said air inflatable clutches up to afirst control air pressure at a rate responsive to actuation of thethrottle means, which first selective inflation means comprises:

1. a first valve means that is actuated by a piloting air pressure tochange the air passages within itself when said piloting air pressurereaches the first control air pressure;

2. a first air branch that leads from the source of pressurized air tosaid first valve means and is operatively connected to said throttlemeans, which first air branch has an air output that is responsive toair pressure supplied to the first air branch by said throttle means;and

3. a third air branch that leads from said first valve means to the airinflatable clutches, which third air branch receives air from the firstair branch through the first valve means until the first control airpressure is reached and the first valve means is actuated;

a second selective inflation means for inflating said selected airinflatable clutch beyond the first control air pressure at a programmedrate up to a second control air pressure at which point the secondselective inflation means is actuated by clutch air pressure to completeinflation of said selected clutch at an unrestricted rate to full clutchair pressure; and

a throttle governor control means adapted to control the throttle speedgovernor to maintain the prime mover at idle speed until the selectedclutch air pressure reaches a third control air pressure and thereafterallow air pressure to be operatively supplied from said throttle meansto the throttle governor for regulation of engine speed by the throttlemeans.

3. The combination of claim 2 wherein the second selective inflationmeans comprises:

the first valve means and the third air branch of the first selectiveinflation means and further includes a second air branch that leads fromthe source of pressurized air to said first valve means; and restrictingvalve means included in the second air branch for restricting the rateof increase of air flowing into the third air branch until the air inthe selected clutch reaches the second control air pressure whereuponthe second air branch is actuated by the selected clutch air pressure tobypass the restricting valve means to complete inflation of the selectedclutch to full clutch air pressure.

4. The combination of claim 2 wherein the throttle governor controlmeans includes a governor valve means operatively connected between thethrottle means and the throttle speed governor,

a piloting air branch supplies air from the selected clutch to thegovernor valve means, and

the governor valve means is adapted to block passage of air to thethrottle speed governor until air pressure supplied to it from saidpiloting air branch reaches the third control air pressure and thereuponactuate to enable the throttle means to actuate the throttle speedgovernor.

5. The combination of claim 3 wherein a piloting air branch supplies airfrom the selected clutch to the second air branch, and the secondselective inflation meansis actuated at the second control air pressureby air pressure operatively supplied by said piloting air branch.

1. A pneumatic clutch control assembly for a marine propulsion system ofthe type including a prime mover controlled by a throttle speedgovernor, a gear drive for transmitting power from the prime mover to apropeller drive shaft, air inflatable clutches arranged to selectivelyconnect the prime mover to the gear drive including at least one suchclutch for ahead operation and at least one such clutch for asternoperation, and throttle means for actuation of the propulsion system,said pneumatic clutch control assembly being adapted for connection to asource of pressurized air and comprising, in combination: a firstselective inflation means that is controlled by the throttle means toinflate a selected one of said air inflatable clutches up to a firstcontrol air pressure at a rate responsive to actuation of the throttlemeans; a second selective inflation means that operates independently ofand bypasses the throttle means for inflating said selected airinflatable clutch beyond the first control air pressure at a programmedrate up to a second control air pressure at which point the secondselective inflation means is actuated by clutch air pressure to completeinflation of said selected clutch at an unrestricted rate to full clutchair pressure; valve means arranged to operatively connect the firstselective inflation means for clutch inflation below the first controlair pressure and further arranged to operatively connect the secondselective inflation means for clutch inflation above the first controlair pressure; a throttle governor control means adapted to control thethrottle speed governor to maintain the prime mover at idle speed untilthe selected clutch air pressure reaches a third control air pressureand thereafter allow air pressure from said first selective inflationmeans to be supplied to the throttle governor for regulation of enginespeed by the throttle means.
 2. A pneumatic clutch control assembly fora marine propulsion system of the type including a prime movercontrolled by a throttle speed governor, a gear drive for transmittingpower from the prime mover to a propeller drive shaft, air inflatableclutches arraNged to selectively connect the prime mover to the geardrive including at least one such clutch for ahead operation and atleast one such clutch for astern operation, and throttle means foractuation of the propulsion system, said pneumatic clutch controlassembly being adapted for connection to a source of pressurized air andcomprising, in combination: a first selective inflation means that iscontrolled by the throttle means to inflate a selected one of said airinflatable clutches up to a first control air pressure at a rateresponsive to actuation of the throttle means, which first selectiveinflation means comprises:
 2. a first air branch that leads from thesource of pressurized air to said first valve means and is operativelyconnected to said throttle means, which first air branch has an airoutput that is responsive to air pressure supplied to the first airbranch by said throttle means; and
 3. The combination of claim 2 whereinthe second selective inflation means comprises: the first valve meansand the third air branch of the first selective inflation means andfurther includes a second air branch that leads from the source ofpressurized air to said first valve means; and restricting valve meansincluded in the second air branch for restricting the rate of increaseof air flowing into the third air branch until the air in the selectedclutch reaches the second control air pressure whereupon the second airbranch is actuated by the selected clutch air pressure to bypass therestricting valve means to complete inflation of the selected clutch tofull clutch air pressure.
 3. a third air branch that leads from saidfirst valve means to the air inflatable clutches, which third air branchreceives air from the first air branch through the first valve meansuntil the first control air pressure is reached and the first valvemeans is actuated; a second selective inflation means for inflating saidselected air inflatable clutch beyond the first control air pressure ata programmed rate up to a second control air pressure at which point thesecond selective inflation means is actuated by clutch air pressure tocomplete inflation of said selected clutch at an unrestricted rate tofull clutch air pressure; and a throttle governor control means adaptedto control the throttle speed governor to maintain the prime mover atidle speed until the selected clutch air pressure reaches a thirdcontrol air pressure and thereafter allow air pressure to be operativelysupplied from said throttle means to the throttle governor forregulation of engine speed by the throttle means.
 4. The combination ofclaim 2 wherein the throttle governor control means includes a governorvalve means operatively connected between the throttle means and thethrottle speed governor, a piloting air branch supplies air from theselected clutch to the governor valve means, and the governor valvemeans is adapted to block passage of air to the throttle speed governoruntil air pressure supplied to it from said piloting air branch reachesthe third control air pressure and thereupon actuate to enable thethrottle means to actuate the throttle speed governor.
 5. Thecombination of claim 3 wherein a piloting air branch supplies air fromthe selected clutch to the second air branch, and the second selectiveinflation means is actuated at the second control air pressure by airpressure operatively supplied by said piloting air branch.